Interlink sensors and/or actuators are now used in numerous ways in various fields, e.g. in the machine and plant industry. The sensors and/or actuators are interlinked by means of a bus system. In order to reduce cabling costs, the bus cable should be brought as close as possible to the sensors. This gives rise to the requirement that the connection corresponds to protection class IP 65 (DIN 40050). The bus cable is typically a two-core, shaped flat cable. Apart from the bus cable, in those uses where several actuators with high power requirements are used, there is also a need for at least one separate, also shaped power supply cable.
The sensors and/or actuators are normally connected by means of at least one coupling module to the bus and the power supply. The coupling module can be installed at random points of the bus system and has cutting contacts for contacting the bus and power supply cable. There are passive and/or active electronic elements within the coupling module. Said elements can e.g. be constituted by an integrated circuit (IC), which converts the serial information transmitted in the bus into the parallel information required in the sensors and/or actuators and vice versa. The IC can also perform other data processing functions.
The individual sensors and/or actuators are connected by means of individual connecting cables to the coupling module. It is desirable for an optimum flexible and user-friendly design, to be able to connect the connecting cables from one or other side to the coupling module. This possibility has not existed in the hitherto known systems. Conventional coupling modules can only be fitted in a specific orientation to the bus and power supply cable, so as to prevent the cable being incorrectly contacted (e.g. with reverse polarity) or not contacted at all. This amounts to a significant restriction with respect to the use of such bus systems.